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Background: Severe aortic insufficiency (AI) with preserved left ventricular (LV) function may be associated with a long asymptomatic period and unpredictable course on medical therapy. Since myocardial wall stress is closely related to both pathologic cardiac remodeling and ultimately to LV decompensation, a more accurate description of regional wall stress may improve our ability to appropriately manage these patients. The objective of this study was to define differences in instantaneous global and regional three-dimensional end-systolic maximum principal stress (ESS) between normal patients and patients with AI, both before and after aortic valve replacement (AVR) using magnetic resonance imaging (MRI) and finite element analysis (FEA)., Methods: Magnetic resonance imaging was performed on 20 normal volunteers and 14 patients with moderate to severe AI with normal systolic function (ejection fraction: 57 +/- 0.6) before and after AVR. Finite element analysis was utilized to estimate global and regional ESS., Results: Both global (p < 0.001) and regional (p < 0.001 in all segments) ESS were significantly higher in the preoperative AI patients when compared with their postoperative values and normal controls. Postoperative ESS was significantly lower than the normal controls (p = 0.002)., Conclusions: Three-dimensional regional and global end-systolic LV wall stress can be determined by MRI and finite element analysis. Values of ESS in patients with chronic AI were elevated prior to AVR and normalized after AVR. This method may have considerable potential as a noninvasive, clinically applicable index of regional LV geometry and function that may help with the serial evaluation of patients with AI.

Background: Left ventricular three-dimensional nonlinear systolic strain determinations have potential to detect small decrements in ventricular function in patients with aortic insufficiency before and after aortic valve replacement., Methods: Magnetic resonance imaging with tissue-tagging was performed on 42 normal volunteers and 14 patients with chronic aortic insufficiency both before and 28 +/- 11 months after aortic valve replacement. Preoperative and postoperative left ventricular volume, dimensions and ejection fraction were determined for all subjects. Left ventricular systolic radial, circumferential, longitudinal, and minimum principal strain were calculated for six left ventricular regions., Results: After aortic valve replacement, left ventricular volume and dimensions decreased significantly (p < 0.001) and ejection fraction increased nonsignificantly (p = 0.096). Strain values in preoperative aortic insufficiency patients did not differ significantly from controls. At an average of 28 +/- 11 months postoperatively, however, regional three-dimensional minimum principal and longitudinal strain was decreased in all six ventricular regions as well as globally (p < 0.03) compared with normal control values. Circumferential strain was significantly decreased globally and in all but two regions (p < 0.03)., Conclusions: These magnetic resonance imaging-based techniques are sensitive enough to detect a previously unrecognized, significant decrease in both global and regional three-dimensional left ventricular systolic strain 2 years after aortic valve replacement for minimally symptomatic chronic aortic insufficiency despite improvement in ejection fraction and a decrease in left ventricular size. The reasons for a significant decline in left ventricular systolic strain after successful aortic valve replacement in minimally symptomatic chronic aortic insufficiency patients are not clear and warrant further investigation.

Background and Aim: Left ventricular (LV) 3D systolic strain decreases in absolute value postoperatively and does not recover in patients who undergo aortic valve replacement (AVR) for chronic aortic insufficiency (AI). We investigated whether choice of valve prosthesis (mechanical [St. Jude], bioprosthetic [bovine pericardial], Ross procedure) had a significant impact on strain recovery in this surgical population., Methods: MRI with tissue-tagging was performed on 14 patients with chronic AI both before and 28 +/- 13 months after AVR. Average values of LV systolic strain and end-systolic stress (ESS) were computed from MRI data for the LV. Three types of prosthetic valve were examined (Ross procedure n = 4, bovine pericardial n = 5, and St. Jude n = 5)., Results: Overall, systolic strain, ESS, LV volumes, ejection fraction, and LV mass all changed significantly following AVR. Comparisons between individual valve types revealed no differences in any of these measurements. Patients who received a mechanical valve had a greater decrease in the absolute value of systolic strain following surgery compared to patients from the nonmechanical group (Ross procedure and bioprosthetic valve). Comparisons between the Ross group and the prosthetic group (St. Jude and bioprosthetic) produced no significant differences in strain, ESS, LV volume, and mass., Conclusions: These early results suggest that valve prosthetic type may be a factor in efforts to improve strain recovery after AVR for AI, although further investigation is warranted. MRI with tissue-tagging may be a useful tool for comparing the impact of prosthetic valve choice on incompletely recovered systolic strain following AVR for chronic AI.